Abstract: The paper proposes the application of nonredundant error-correction in differential demodulation combined with soft-decision decoding. According to the hard-decision information of nonredundant error-correction, the soft output of conventional differential demodulation is weighted. Thus nonredundant error-correction can be used in a system in which the differential demodulation is combined with soft-decision decoding. The algorithm improves the performance of system. Computer simulation shows that the improved performance of the proposed algorithm is superior to the conventional differential demodulation combined with soft-decision decoding by 1.4dB at a BER of 10^-5 in AWGN channel. In Rician channel there is the same notable performance improvements. It enables nonredundant error-correction to be used in the system of differential demodulation combined with soft-decision decoding which is widely used in satellite communication system. The system's capacity and communication quality is notably improved.

Key words: satellite mobile channel, nonredundant error-correction, differential demodulation, soft-decision decoding, metrics weighting